Semi-trailer trucks typically include at least one vertical exhaust stack positioned rear of or alongside the truck cab. The vertical exhaust stack is normally secured to a side or rear surface of the truck cab. Other portions of the exhaust system, such as exhaust after-treatment devices, are often attached to the vehicle frame. Because the truck cab is moveably mounted to the frame of the vehicle, when the semi-trailer truck is in motion, there is necessarily relative movement between the exhaust stack and those exhaust system components that are mounted to the frame.
Some vehicles include an exhaust system support assembly that allows for a certain amount of relative motion between the exhaust stack and the vehicle cab. Thus, the exhaust stack is free to move with the frame-mounted exhaust system components free from the restriction that would result from rigidly mounting the exhaust stack to the vehicle cab. Nonetheless, these support assemblies often restrict the motion of the cab at the extreme positions of cab movement during jounce and rebound. This restriction can cause the exhaust system support assembly to be torn away from the truck cab when the truck cab moves beyond the limits to which the support assembly is designed to accommodate.
Other known exhaust systems include a section of flexible hose between the frame-mounted and cab-mounted portions of the exhaust system. The flexible hose provides a conduit from the frame-mounted portion to the cab-mounted portion, while allowing for relative motion therebetween. Still, such exhaust systems are not without disadvantages. For example, many vehicle operators take great pride in the appearance of their vehicles, often outfitting the vehicles with highly polished chrome exhaust system components. For these systems, a flexible hose, which can not be chromed and polished to match the other exhaust components, detracts from the overall appearance of the vehicle.
Operators of semi-trailer trucks would find desirable an exhaust system assembly that allows for relative motion between the cab-mounted exhaust stack and the frame-mounted exhaust components during jounce and rebound, while providing an aesthetically pleasing appearance.